I am sorry you found the Romanian translations unprofessional. Are you reffering to a certain project (core, meta, a plugin, a theme)? Please give us some examples.
You can see Romanian projects here https://translate.wordpress.org/locale/ro/default/
Who decided who will be the team leader?
The international reps are chosen by the community based on one’s involvement.
The locale General Translation Editors (GTE) are picked by the current team from those who show up and translate, after they demonstrate that they follow the general translation rules, style guidelines and glossary.
You can read our translation guide here.
In that handbook you also find information about how to become a Project Translation Editor or a GTE.
How much does WordPress pay for localization?
WordPress is an open-source project so unless someone is sponsored to contribute, there is no payment. All Romanian contributors are volunteers as far as I know. Some companies that own plugins/themes choose to hire professional translators for their plugin but those translations will come from special Cross Language Project Translation Editor accounts (CLPTE).
Hope this information helps. Let us know if you have more specifics on what can be improved and we’d be more than happy to discuss.